Originally shared by Sam De La Haye
Just got back the prices of how much it will cost, to have the base pf my milling machine machined and on my budget its not really possible at the moment. Had a thought of whether I could do it myself, with a high degree of accuracy.
I came up with an idea and would love to know if anyone’s done something similar, or has any thoughts for and or against!
The aim is to build an adjustable tower, which would be set to exactly 90 degrees to the areas where the rails will go, using the comparateur to do so.
Next the rails I have for this project, would be mounted to the side of the milling machine using L shape brackets. Aligned again using the same comparateur, so within 1/100 of a millimeter.
After the rails are exactly aligned with one another, I mount a small grinder ( which still needs some thought ) to machine very careful both side to the same plane.
Would love to hear what you think!
When you have more time than money, you can always do it by hand. Scrape it. Lap it with sandpaper on a surface plate. Hard to get to areas? Use sand paper on parallels or 1-2-3 blocks. It honestly doesn’t take that long. You are looking for flat, not polished.
@David_Kirtley Im glad to hear its at least possible! Sounds like you’re talking from experience, definitely some great ideas I’m looking forward to putting into action! How long just roughly how long it might take? Thanks! 
Most of my experience is with little stuff but as long as you are taking little material off and measure often, you really can’t go wrong.
Basic principle is to use a reference surface covered with transfer marking goop (usually a prussian blue transfer dye) by putting the part and the reference in contact. Scrape the high points on the part that the goop sticks to. Repeat until the surface is as flat as you have the patience for. A really good starting place is:
https://www.youtube.com/watch?v=YvZFOyo63Ks
It is complete overkill for the plane he is working on but a really good example of the entire process.
This is the traditional way to do machine parts and when you want parts that REALLY fit well. (As good or better than you can do with any machine) As far as time? You get the surfaces close with more “assertive” technology. You can move a lot of metal really quickly with coarse abrasives under power.
@David_Kirtley Thanks for the brillant video and excellent advice! I’ve just finished off the plans for my measuring tower, which I will post now, really looking forward to getting this part of the project moving. Thanks again! Hope you have a great weekend!
Not only the ‘tower’ need to be precisely 90 deg (by the way, how do you intend to achieve this?), but he should turn around an axis which has to be, also, precisely peeerp to the guides plane… Not an easy task…
More, the circular guides should be not only sharp ‘leveled’, but they should be mounted with liniarity precision. Remember, by grinding you will copy those guides to your machined surfaces. The thk rails will ‘copy’ themselves those surfaces.
What accuracy you are looking for?
The YT video mr. Kirtley is suggesting is really interesting and is about what a (skilled) human hand can do. But it is more about planeity which is form precision. Obtained by ‘shaving’ a surface until can be compared with an etalon surface.
Your specific problem deals more with the precision of the position, which is another thing.
@Alex_Paverman The aim is to use the comparateur to align the tower to exactly 90 degress, just like tramming the head on a mill. Thanks for the input, hopefully this project will move forward soon!
